Editors' Summary: Twenty-five years ago, Congress enacted the ESA with the goal of conserving endangered and threatened species, as well as the ecosystems on which they depend. How successful the Act has been in achieving that goal has been the subject of much controversy. This Dialogue assesses the Act's success by examining one aspect of its history — the experience that has resulted from applying its provisions to private land. From this assessment, the author determines that there are four lessons that can be learned. First, limitations on the Act's prohibition on "taking" protected species indicate that this provision alone cannot effectively address many of the most serious threats to these species. Second, the prohibition has prompted many landowners to modify their land in order to prevent the application of the Act to their property. Third, positive incentives can encourage private landowners to take steps to benefit protected species. And fourth, the Act's habitat conservation planning provisions can be used creatively to benefit species located on private land.